Mud dauber (sometimes called “dirt dauber,” “dirt digger,” “dirt dobber,” “dirt diver”, or “mud wasp”) is a name commonly applied to a number of wasps from either the family Sphecidae or Crabronidae that build their nests from mud.

Mud daubers are long, slender wasps about 1-inch (25 mm) in length; the latter two species above have thread-like waists. The name of this wasp group comes from the nests that are made by the females, which consist of mud molded into place by the wasp’s mandibles.